LAB

Title: Investigating Rocks and Minerals Aim: To determine the appropriate percentage of limestone rocks Apparatus/Materials: Tweezer/dropper/tongs, vinegar, plastic cup/ petri dish, plastic conainers, stones.Method: Collect 50 small stones within Mandeville region. Wash them gently in water and dried them in sunlight, The rocks were placed in a cup, which contained vinegar. Then the observations were recorded.Calculations: There are 26 limestone rocks in the table. To find the percentage 26 must be placed over 50 and then multiplied by 100.26/50 x 100 = 52%Discussion: Limestone is a sedimentary rock composed largely of the mineral calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Most limestone are composed from skeletal fragments of marine organisms such as coral. In this experiment, each rock sample was placed in a plastic cup which contained vinegar.Limestone reacts with vinegar. Like chalk and marble, it reacts because it is a type of calcium carbonate. Common rocks such as flint, granite, and sandstone are unaffected. Vinegar works along contacts between mineral grains. Crystals that are tightly bound together become looser as weathering products, such as vinegar, form at their contacts.

Observation: Igneous rocks, such as granite, are usually the hardest. Sedimentary rocks, such as sandstone, are usually the softest. Each rock sample had different reactions when they were placed into vinegar. The limestone rocks fizzed a lot of bubble, the slightly limestone rocks fizzed a little and the rocks that were not limestone did not fizz at all. Also when vinegar came in contact with the rocks, ony some of the colour of the rocks were slighlty change to a lighter colour.

Conclusion: Vinegar which contains acetic acid, react with the minerals found in limestones called calcium carbonate and not with other rocks such igneous rocks.